The invention relates to a method for making contact with a semiconductor and also to a contact arrangement for a semiconductor.
In the case of so-called high power applications, in which high power outputs are switched, devices for producing a contact arrangement are soldered generally as components without a housing, so-called “bare-dies” onto substrates, such as for example direct bonded copper (DBC), insulated metal substrate (IMS) etc., and/or onto circuit boards and/or onto lead frames or the like. The semiconductors are surface-connected to at least one first contact partner on at least one first surface by means of providing a first solder layer that has a predetermined thickness. One problem in this case resides in the fact that the semiconductor that is not laterally guided can float out of position on the solder layer so that the semiconductor does not retain the original position but rather moves sideward on the substrate. This lateral movement can be prevented by means of suitable measures. These measures differ from contact partner to contact partner.
In addition, the semiconductor in the case of the above mentioned high-power applications is not only soldered on the contact face that is facing the first contact partner but rather said semiconductor also makes contact with a second contact partner by means of providing a second solder layer with a second contact surface. Contact with the first contact surface is generally made by way of a metal clip and/or a metal bridge but in some cases also by way of a suitable DBC. The underside is generally an insulated metal block for the purpose of storing or distributing heat, however said underside can also be a different substrate.
The unexamined German application DE 103 32 695 A1 describes, by way of example, an arrangement for fastening a device to at least one substrate. In the case of the described arrangement, a solder layer is provided on a solder site of the device, wherein the solder site is arranged on the upper surface that faces the respective substrate. Furthermore, at least one recess is provided in the respective substrate for the purpose of receiving any excess solder and/or for the purpose of restricting the solder to the upper surface of the carrier. The substrate upper surface that has the recess faces the solder site of the device.
The printed patent specification U.S. Pat. No. 4,935,803 describes a contact arrangement for a component. In the described contact arrangement, the component is surface-connected to at least one first contact partner on at least one first surface by means of providing a first solder layer, wherein the first contact partner is embodied as an electrical contact bracket. Furthermore, the component is surface-connected to a second contact partner on a second surface by means of providing at least one second solder layer. A convex bracket shape prevents the first solder layer from running off course and provides a self-centering arrangement for the bracket of the component.